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Federal Register / Vol. 86, No. 35 / Wednesday, February 24, 2021 / Rules and Regulations
observed the NOAEL and the lowest dose at which adverse effects of concern are identified the LOAEL. Uncertainty/
safety factors are used in conjunction with the POD to calculate a safe exposure levelgenerally referred to as a population-adjusted dose PAD or a reference dose RfDand a safe margin of exposure MOE. For non-threshold risks, the Agency assumes that any amount of exposure will lead to some degree of risk. Thus, the Agency estimates risk in terms of the probability of an occurrence of the adverse effect expected in a lifetime. For more information on the general principles EPA uses in risk characterization and a complete description of the risk assessment process, see http
www2.epa.gov/pesticide-science-andassessing-pesticide-risks/assessinghuman-health-risk-pesticides.
Based on a thorough analysis of the toxicology database of tetraniliprole, the Agency has determined that a qualitative risk assessment is more appropriate for tetraniliprole based on the following reasons:
All the adverse effects decrease in pup body weights and non-neoplastic uterine lesions, characterized by prolapsed vagina, squamous cell hyperplasia in the cervix in rats were found at or slightly above the limit dose.
Although informative for hazard characterization for purposes of risk assessment, a toxicity test dose at or above the limit dose of 1,000 mg/kg/day represents an exposure that is not expected to occur either daily or over an extended period of time and therefore is not relevant to exposure levels expected from the use of tetraniliprole.
EPA determined that the body weight reduction effects seen in the 90day and 1-year oral studies with the dog, approximately 500 mg/kg/day were not robust enough to be employed as a toxicity endpoint for risk assessment, due to the marginal nature of those effects and the fact that the rat for which effects were seen at the 1,000
mg/kg/day, limit dose was more sensitive, based on a human equivalent dose analysis.
Available data indicate no potential inhalation risk of concern.
Available data indicate no adverse systemic effects at the limit dose 1,000
mg/kg/day for dermal exposure.
Potential offspring susceptibility was not of concern as the decrease in pup weight seen in the reproduction study was marginal and occurred at or above the limit dose 890/1,032 mg/kg/
day males/females. In addition, the decrease occurred on postnatal days PND 14 to 21, at which time the pups were likely to be exposed to the test
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material through both milk and feed resulting in a much higher compound intake.
Finally, taking into account expected exposures, EPA does not anticipate dietary exposure levels to occur daily, or over an extended period of time that would reach levels anywhere near that of the limit dose 1,000 mg/kg/day. An unrefined chronic dietary food only exposure estimate of tetraniliprole was calculated using tolerance-level residues for all crops and assuming 100% crop treated, as well as default processing factors.
The screening estimate indicated that the highest exposure group is children 1 to 2 years old, with an estimated exposure of 0.027 mg/kg/day. To reach a dose of 1,000 mg/kg/day, an individual of this subpopulation would need to ingest 37,000 times the estimated dietary exposure. Further, the highest current application rate is approximately 0.18 lb ai/acre; and in order to yield residues that would lead to dietary exposures of 1,000 mg/kg/day, the application rate would have to be greater than 6,000 lb ai/acre.
Consequently, EPA does not believe that an effect at or about the limit dose is relevant to human health risk assessment for tetraniliprole.
Taking all the foregoing into consideration, EPA has concluded that a qualitative analysis of tetraniliprole is appropriate.
C. Exposure Assessment 1. Dietary exposure from food and feed uses. There is potential for exposure to tetraniliprole via food and feed based on the proposed uses.
However, no adverse effects were observed in the submitted toxicological studies for tetraniliprole regardless of the route of exposure. Thus, no quantitative dietary exposure assessments are needed for EPA to conclude with reasonable certainty that dietary exposures to tetraniliprole do not pose a significant human health risk.
2. Dietary exposure from drinking water. There are no residues of toxicological concern expected in drinking water from the use of tetraniliprole. Thus, no drinking water exposure assessments are needed for the Agency to conclude with reasonable certainty that drinking water exposures to tetraniliprole do not pose a significant human health risk.
3. From non-dietary exposure. The term residential exposure is used in this document to refer to nonoccupational, non-dietary exposure e.g., for lawn and garden pest control,
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indoor pest control, termiticides, and flea and tick control on pets.
Based upon the proposed labels, EPA
does not anticipate residential handler exposures. Tetraniliprole is being proposed for registration as a liquid formulation for use on golf course turf and sports fields that could result in residential post-application exposures.
However, no adverse effects were observed in the submitted toxicological studies for tetraniliprole regardless of the route of exposure; therefore, a quantitative residential post-application exposure assessment was not conducted. Thus, no residential exposure assessments are needed for the Agency to conclude with reasonable certainty that residential exposures to tetraniliprole do not pose a significant human health risk.
4. Cumulative effects from substances with a common mechanism of toxicity.
Section 408b2Dv of FFDCA
requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider available information concerning the cumulative effects of a particular pesticides residues and other substances that have a common mechanism of toxicity.
EPA has not found tetraniliprole to share a common mechanism of toxicity with any other substances, and tetraniliprole does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has assumed that tetraniliprole does not have a common mechanism of toxicity with other substances. For information regarding EPAs efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see EPAs website at http
www2.epa.gov/pesticide-science-andassessing-pesticide-risks/cumulativeassessment-risk-pesticides.
D. Safety Factor for Infants and Children Section 408b2C requires the application of an additional tenfold margin of safety to account for potential risks to infants and children, in the case of threshold effects. For tetraniliprole, EPA has not identified any toxicological endpoints of concern associated with any threshold effects and is conducting a qualitative assessment. That qualitative assessment does not use safety factors for assessing risk, and no additional safety factor is needed for assessing risk to infants and children.
EPA has also evaluated the available data and concluded that there are no residual uncertainties concerning the
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